1. Field of the Invention
The present invention relates to a method for measuring the dimensions of an optical connector which is provided with a ferrule having an optical fiber or fibers to be inserted and fixed into one or a plurality of fiber inserting holes, and a plurality of pin holes to which a plurality of positioning guide pins are fitted, wherein the position or positions of said fiber inserting hole or holes are measured using said pin holes as the reference.
2. Description of Related Art
An optical connector consists of a single or multi optical fibers installed on a ferrule which has positioning pin holes for butt-connection. An optical connector which uses a single optical fiber is referred to as a single connector, and one that uses multiple optical fibers is referred to as a multi connector.
Among such optical connectors, a multi connector, for instance, has a plurality of fiber inserting holes formed in a plastic ferrule at regular arranging pitches, and the individual optical fibers of the multi fiber are inserted in those respective fiber inserting holes, then they are fixed with an adhesive agent. To butt such multi connector against a mating multi connector, the guide pins are fitted to the pin holes of both to position them for butt-connection. Thus, matching optical fibers are optically connected each other. The same applies to a single connector.
In said optical connector, a connection loss inherent to the butt-connection with another optical connector is minimized by aligning the optical axes of the individual optical fibers. For this reason, the fiber inserting holes require precision machining of a submicron order.
Because of such requirement, in optical connectors or ferrules, the dimension measurement is conducted to inspect the positions of the fiber inserting holes in order to ensure quality control for screening for nondefectives by judging whether a manufactured optical connector is defective or nondefective. In the dimension measurement of a ferrule, for example, an inspection light is irradiated to a butting surface of a ferrule whose fiber inserting holes are all exposed, and the inspection light reflecting from the butting surface, that is, a reflecting light, is used to perform optical measurement of the position of each fiber inserting hole by a position measuring means.
However, when the fiber inserting holes are measured using the reflecting light as described above, there was a problem that a measurement error which is not permissible at the submicron level results if a circumferential edge of a fiber inserting hole is chipped or if the hole shape is distorted.
As explained already, optical connectors are positioned by fitting the guide pins into the pin holes of both optical connectors, thus properly connecting them. Therefore, the measurement of the fiber inserting holes requires position measurement based on the pin holes.
However, it is necessary to measure the pin holes and the fiber inserting holes separately because the diameter of the pin holes is a few times larger than that of the fiber inserting holes. This makes the measurement extremely complicated with an insufficient measurement accuracy.